Recently, the U.S. Court of Appeals for the Federal Circuit issued a decision in Sisvel International S.A. v. Sierra Wireless, Inc., et al., Nos. 2022-1493, -1547 (Oct. 6, 2023).
Sierra Wireless (“Sierra”) petitioned for inter partes review challenging several claims of Sisvel’s U.S. Patent No. 6,529,561 as unpatentable due to obviousness. Some claims were the subject of a single reference (Chen) challenge, while others were challenged based on the combination of Chen with other references. “The Board determined that Chen rendered claims 1-3 and 9 obvious, but upheld claims 4-8 and 10.” As to claim 5, the Board construed “means for detecting” as a means-plus-function limitation and found insufficient algorithmic structure identified in the specification. As such, the Board did not assess claims 5-8 and 10 against Chen alone because it was unable to conclude what structure is encompassed by the “means for detecting” limitation. The Board rejected the grounds based on Chen combined with other references due to insufficient motivation to combine. Both parties appealed.
On the issues appealed by Sisvel, the Federal Circuit affirmed. The Court held there was substantial evidence that the subject claims were invalid and rejected Sisvel’s argument that the prior art taught away from the claimed technique. The Court likewise rejected Sisvel’s assertion that the Board failed to adequately consider its arguments, noting that the Board explicitly acknowledged and adequately addressed them in a manner supported by substantial evidence.
On the issues appealed by Sierra, the Court reached a mixed result. Starting with Sierra’s challenge to the Board’s finding of no motivation to combine, the Court agreed with the Board that Sierra’s arguments were insufficiently specific, too generic, and inconsistent. The Court affirmed the Board’s rejection of what it characterized as Sierra’s “kitchen-sink of unclear and confusing motivation-to-combine arguments.”
On the means-plus-function issues, however, the Court vacated the Board’s decision. Specifically, the Court held that because the specification had some disclosure of structure, the Board should have considered offered expert testimony on the knowledge of a skilled artisan. The Court further held that if, on remand, the Board still concludes there is insufficient corresponding structure, it must either (1) determine whether the claim is indefinite or (2) resolve the prior art challenge despite potential indefiniteness, and must “clearly state that the final written decision does not include a determination of patentability of any claim that falls within the impossibility category.”